This invention relates to an optical system which incorporates a raster-scan imager.
For security and other purposes there is frequently a requirement for a surveillance system which can be used to examine a wide angle field (often 360.degree.) in a short space of time. However, if an imager having a T.V. raster scan pattern is mounted on a support and rotated rapidly in azimuth, significant rotation occurs during the time required for a complete raster frame scan so that the resulting picture is skewed, i.e. distorted. While this is acceptable for low rotation rates the amount of distortion becomes intolerable if the azimuth rotation rate is comparable with the frame scanning rate.